https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108646
Bug ID: 108646
Summary: nonnull attribute does not detect variables that are
NULL being passed
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jg at jguk dot org
Target Milestone: ---
If we pass NULL directly, there is a good warning (pasted below from today on
Godblot.org latest gcc trunk)
However, there is no error if passing a variable set to NULL.
Could gcc detect this situation?
#include <cstddef>
void * mem2(void *dest) __attribute__((nonnull));
void test(void)
{
char *dest = NULL;
mem2(dest);
}
This is the warning when NULL is passed directly:
<source>: In function 'void test()':
<source>:6:6: warning: argument 1 null where non-null expected [-Wnonnull]
6 | mem2(NULL);
| ~~~~^~~~~~
<source>:2:8: note: in a call to function 'void* mem2(void*)' declared
'nonnull'
2 | void * mem2(void *dest) __attribute__((nonnull));
| ^~~~
Compiler returned: 0
